1 /*
2 * RSA/SHA-256 signature verification program
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19
20 #if !defined(MBEDTLS_CONFIG_FILE)
21 #include "mbedtls/config.h"
22 #else
23 #include MBEDTLS_CONFIG_FILE
24 #endif
25
26 #if defined(MBEDTLS_PLATFORM_C)
27 #include "mbedtls/platform.h"
28 #else
29 #include <stdio.h>
30 #include <stdlib.h>
31 #define mbedtls_printf printf
32 #define mbedtls_snprintf snprintf
33 #define mbedtls_exit exit
34 #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
35 #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
36 #endif /* MBEDTLS_PLATFORM_C */
37
38 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) || \
39 !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \
40 !defined(MBEDTLS_FS_IO)
main(void)41 int main( void )
42 {
43 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_RSA_C and/or "
44 "MBEDTLS_MD_C and/or "
45 "MBEDTLS_SHA256_C and/or MBEDTLS_FS_IO not defined.\n");
46 mbedtls_exit( 0 );
47 }
48 #else
49
50 #include "mbedtls/rsa.h"
51 #include "mbedtls/md.h"
52
53 #include <stdio.h>
54 #include <string.h>
55
56
main(int argc,char * argv[])57 int main( int argc, char *argv[] )
58 {
59 FILE *f;
60 int ret = 1;
61 unsigned c;
62 int exit_code = MBEDTLS_EXIT_FAILURE;
63 size_t i;
64 mbedtls_rsa_context rsa;
65 unsigned char hash[32];
66 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
67 char filename[512];
68
69 mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );
70
71 if( argc != 2 )
72 {
73 mbedtls_printf( "usage: rsa_verify <filename>\n" );
74
75 #if defined(_WIN32)
76 mbedtls_printf( "\n" );
77 #endif
78
79 goto exit;
80 }
81
82 mbedtls_printf( "\n . Reading public key from rsa_pub.txt" );
83 fflush( stdout );
84
85 if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
86 {
87 mbedtls_printf( " failed\n ! Could not open rsa_pub.txt\n" \
88 " ! Please run rsa_genkey first\n\n" );
89 goto exit;
90 }
91
92 if( ( ret = mbedtls_mpi_read_file( &rsa.N, 16, f ) ) != 0 ||
93 ( ret = mbedtls_mpi_read_file( &rsa.E, 16, f ) ) != 0 )
94 {
95 mbedtls_printf( " failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret );
96 fclose( f );
97 goto exit;
98 }
99
100 rsa.len = ( mbedtls_mpi_bitlen( &rsa.N ) + 7 ) >> 3;
101
102 fclose( f );
103
104 /*
105 * Extract the RSA signature from the text file
106 */
107 mbedtls_snprintf( filename, sizeof(filename), "%s.sig", argv[1] );
108
109 if( ( f = fopen( filename, "rb" ) ) == NULL )
110 {
111 mbedtls_printf( "\n ! Could not open %s\n\n", filename );
112 goto exit;
113 }
114
115 i = 0;
116 while( fscanf( f, "%02X", (unsigned int*) &c ) > 0 &&
117 i < (int) sizeof( buf ) )
118 buf[i++] = (unsigned char) c;
119
120 fclose( f );
121
122 if( i != rsa.len )
123 {
124 mbedtls_printf( "\n ! Invalid RSA signature format\n\n" );
125 goto exit;
126 }
127
128 /*
129 * Compute the SHA-256 hash of the input file and
130 * verify the signature
131 */
132 mbedtls_printf( "\n . Verifying the RSA/SHA-256 signature" );
133 fflush( stdout );
134
135 if( ( ret = mbedtls_md_file(
136 mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 ),
137 argv[1], hash ) ) != 0 )
138 {
139 mbedtls_printf( " failed\n ! Could not open or read %s\n\n", argv[1] );
140 goto exit;
141 }
142
143 if( ( ret = mbedtls_rsa_pkcs1_verify( &rsa, NULL, NULL, MBEDTLS_RSA_PUBLIC,
144 MBEDTLS_MD_SHA256, 20, hash, buf ) ) != 0 )
145 {
146 mbedtls_printf( " failed\n ! mbedtls_rsa_pkcs1_verify returned -0x%0x\n\n", (unsigned int) -ret );
147 goto exit;
148 }
149
150 mbedtls_printf( "\n . OK (the signature is valid)\n\n" );
151
152 exit_code = MBEDTLS_EXIT_SUCCESS;
153
154 exit:
155
156 mbedtls_rsa_free( &rsa );
157
158 #if defined(_WIN32)
159 mbedtls_printf( " + Press Enter to exit this program.\n" );
160 fflush( stdout ); getchar();
161 #endif
162
163 mbedtls_exit( exit_code );
164 }
165 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_SHA256_C &&
166 MBEDTLS_FS_IO */
167
